Closed experimental device for extracting formaldehyde from polyformaldehyde granules

Abstract

The utility model relates to the technical field of gas extraction, in particular to a closed experimental device for extracting formaldehyde from polyformaldehyde granules, which comprises a melt index instrument, a beaker with an upper nozzle and a lower nozzle, a mendole-type washing bottle and a peristaltic pump, a charging barrel is arranged in a box body of the melt index instrument, and the beaker with the upper nozzle and the lower nozzle is arranged at an outlet of the charging barrel. The beaker with the upper nozzle and the lower nozzle and the melt index instrument are sealed through a sealing ring gasket, a first gas pipeline is communicated between a beaker outlet pipe and the Menthol-type washing bottle, a second gas pipeline is communicated between the Menthol-type washing bottle and a beaker inlet pipe, and a peristaltic pump is installed on the second gas pipeline. The device disclosed by the utility model is reasonable and compact in structure and convenient to use, improves the accuracy of extracting the formaldehyde content from the polyformaldehyde granules, and provides powerful data support for a polyformaldehyde production process of an enterprise.

Description

Technical Field

[0001] This utility model relates to the field of gas extraction technology and is a closed experimental device for extracting formaldehyde from polyoxymethylene granules. Background Technology

[0002] Polyoxymethylene (POM) is a white, flammable crystalline powder with a formaldehyde odor. Its melting point is 121°C to 123°C, flash point is 71.1°C, and auto-ignition point is 300°C. POM is a linear polymer with no side chains, high density, and high crystallinity, possessing excellent comprehensive properties. It is known as "super steel" or "acetal," exhibiting hardness, strength, and rigidity similar to metals. POM is widely used in electronics, machinery, instrumentation, light industrial products, automobiles, building materials, and agriculture. Specific applications include manufacturing various sliding and rotating mechanical parts, such as gears, levers, pulleys, and sprockets, and it is particularly suitable for bearings, hot water valves, precision metering valves, conveyor chain links, and rollers.

[0003] The production process of polyoxymethylene (POM) granules involves evaporating 37% formaldehyde under reduced pressure, followed by catalytic condensation to obtain solid formaldehyde. This solid formaldehyde is then filtered, washed with water, and vacuum dried to obtain the finished product, which typically contains 93% to 95% formaldehyde. In the production process of POM granules, the formaldehyde content is frequently measured. This data provides crucial information for the POM production process, ensuring that the POM granule product meets the expected performance requirements.

[0004] Currently, the laboratory determination of formaldehyde content in polyoxymethylene (POM) granules involves first heating and melting the POM granules using a melting device, then collecting the gases released during the melting process using a gas collection device, and finally dissolving the collected gases in a water-filled dissolving device to obtain a formaldehyde solution. According to the principle of HJ 601-2011 "Determination of Formaldehyde in Water - Acetylacetone Spectrophotometric Method," the formaldehyde solution reacts with the colorimetric reagent acetylacetone to generate a colored compound, and the absorbance is measured at a wavelength of 414 nm to obtain the formaldehyde content value. However, the connection interfaces between the existing POM melting equipment, formaldehyde gas collection equipment, and formaldehyde solution collection equipment are not standardized according to national standards. Therefore, the airtightness of the connections between these devices is low. This low airtightness can lead to incomplete dissolution of formaldehyde gas in the water during the experiment, ultimately resulting in a lower-than-expected formaldehyde content. Furthermore, the release of formaldehyde gas during the experiment causes environmental pollution.

[0005] In summary, the large error in formaldehyde content extraction from polyoxymethylene (POM) granules has led to incorrect performance indicators in the POM production process, causing serious economic losses and becoming a pressing technical problem that enterprises need to solve. Summary of the Invention

[0006] This invention provides a closed experimental device for extracting formaldehyde from polyoxymethylene granules, which overcomes the shortcomings of the prior art and can effectively solve the problem of large errors in the formaldehyde content extracted from polyoxymethylene granules.

[0007] The technical solution of this utility model is achieved through the following measures: a closed experimental device for extracting formaldehyde from polyoxymethylene granules, including a melt indexer, a beaker with upper and lower nozzles, a Mendelssohn washing bottle, and a peristaltic pump. The melt indexer housing is equipped with a material cylinder, and the bottom outlet of the material cylinder is correspondingly provided with an upward-opening beaker with upper and lower nozzles. The mouth of the beaker with upper and lower nozzles is sealed to the bottom of the melt indexer housing by a sealing ring gasket. The upper part of the beaker with upper and lower nozzles is fixedly connected to a beaker inlet pipe, and the lower part of the beaker with upper and lower nozzles is fixedly connected to a beaker outlet pipe. A first gas pipeline is fixedly connected between the beaker outlet pipe and the top inlet of the Mendelssohn washing bottle, and a second gas pipeline is fixedly connected between the top outlet of the Mendelssohn washing bottle and the beaker inlet pipe. A peristaltic pump is fixedly installed on the second gas pipeline.

[0008] The following are further optimizations and / or improvements to the above-mentioned utility model technical solution:

[0009] The aforementioned sealing gasket is a polytetrafluoroethylene (PTFE) sealing gasket.

[0010] The aforementioned beaker with upper and lower spouts is also equipped with a lifting platform at the bottom.

[0011] The bottom of the aforementioned Meng-style wash bottle is also equipped with a heating furnace.

[0012] The above-mentioned Meng-style wash bottle has a fixed air inlet at the top connected to a washing air pipe, the air outlet of the washing air pipe extends to the bottom of the Meng-style wash bottle, and the air outlet at the top of the Meng-style wash bottle has a fixed air outlet connected to a wash bottle air outlet pipe.

[0013] A first gas pipeline is fixedly connected between the outlet pipe of the aforementioned beaker and the inlet of the gas washing pipe.

[0014] A second gas line is fixedly connected between the gas outlet of the aforementioned bottle washing pipe and the inlet pipe of the beaker.

[0015] Both the first gas pipeline and the second gas pipeline mentioned above are plastic flexible hoses.

[0016] A bottle washing inlet valve is fixedly installed on the aforementioned first gas pipeline.

[0017] A bottle washing outlet valve is fixedly installed on the aforementioned second gas pipeline.

[0018] This utility model has a reasonable and compact structure and is easy to use. It uses a sealing ring gasket to avoid gaps between the mouth of the beaker with upper and lower spouts and the melt indexer, and establishes exhaust gas circulation to reduce formaldehyde gas escape, improve the accuracy of formaldehyde extraction, and provide accurate and reliable technical support for the polyoxymethylene production process. Attached Figure Description

[0019] Appendix Figure 1 This is a schematic diagram of the process flow of this utility model.

[0020] Appendix Figure 1 The codes in the table are as follows: 1 is melt indexer, 2 is beaker with top and bottom nozzles, 3 is Meng-style wash bottle, 4 is peristaltic pump, 5 is material cylinder, 6 is sealing ring gasket, 7 is beaker inlet pipe, 8 is beaker outlet pipe, 9 is first gas line, 10 is second gas line, 11 is lifting platform, 12 is heating furnace, 13 is washing gas pipe, 14 is wash bottle outlet pipe, 15 is wash bottle inlet valve, and 16 is wash bottle outlet valve. Detailed Implementation

[0021] This utility model is not limited to the following embodiments, and the specific implementation method can be determined according to the technical solution of this utility model and the actual situation.

[0022] Unless otherwise specified, all equipment and devices used in this invention are existing, publicly known, and commonly used equipment and devices in the field.

[0023] In this utility model, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as the positional relationships of front, back, top, bottom, left, and right, which are based on the instructions attached. Figure 1 The orientation of the layout is determined by the direction of the map.

[0024] The present invention will be further described below with reference to the embodiments and accompanying drawings:

[0025] Example 1: As shown in the attached document Figure 1 As shown, the closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules includes a melt indexer 1, a beaker with upper and lower nozzles 2, a Mendelssohn washing bottle 3, and a peristaltic pump 4. The melt indexer 1 is equipped with a material cylinder 5 inside its chamber. The bottom outlet of the material cylinder 5 is correspondingly provided with an upward-opening beaker with upper and lower nozzles 2. The mouth of the beaker with upper and lower nozzles 2 is sealed to the bottom of the melt indexer 1 chamber by a sealing ring gasket 6. The upper part of the beaker with upper and lower nozzles 2 is fixedly connected to a beaker inlet pipe 7, and the lower part of the beaker with upper and lower nozzles 2 is fixedly connected to a beaker outlet pipe 8. The beaker outlet pipe 8 and the top inlet of the Mendelssohn washing bottle 3 are fixedly connected to a first gas line 9. The top outlet of the Mendelssohn washing bottle 3 and the beaker inlet pipe 7 are fixedly connected to a second gas line 10. The peristaltic pump 4 is fixedly installed on the second gas line 10.

[0026] As needed, the melt flow indexer 1 can be a Vicomet WKT-550TC precision melt flow rate meter.

[0027] As needed, peristaltic pump 4 can be the Chuangrui brand digital transmission peristaltic pump ON103C.

[0028] The above-mentioned closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules can be further optimized and / or improved according to actual needs:

[0029] Example 2: Its difference from Example 1 is as follows: (See attached) Figure 1 As shown, sealing gasket 6 is a polytetrafluoroethylene sealing gasket.

[0030] As needed, the diameter of the sealing gasket 6 can be matched with the diameter of the mouth of the beaker 2 with upper and lower spouts, which can enhance the sealing between the mouth of the beaker 2 with upper and lower spouts and the bottom of the melt indexer 1.

[0031] Example 3: Its difference from Examples 1 to 2 is as follows: (See attached) Figure 1 As shown, the bottom of the beaker 2 with upper and lower spouts is also equipped with a lifting platform 11.

[0032] As needed, the lifting platform 11 can be a Z-axis lifting slide, which can be a Dongchen Precision ZLJG120 / HTZ210 lifting platform. The lifting platform 11 is used to support the beaker 2 with upper and lower nozzles, which can enhance the sealing between the mouth of the beaker 2 with upper and lower nozzles and the bottom of the melt indexer 1.

[0033] Example 4: Its difference from Examples 1 to 3 is as follows: (See attached) Figure 1 As shown, a heating furnace 12 is also provided at the bottom of the Meng-style washing bottle 3.

[0034] As needed, the heating furnace 12 can be a LICHEN brand digital display far-infrared enclosed electric furnace. The solubility of formaldehyde gas at 25℃ is 55 g / 100 ml water. To maintain good solubility of formaldehyde gas in the Mendelssohn wash bottle 3, when the ambient temperature is low in winter, the heating furnace 12 can preheat and maintain the temperature of the solution in the Mendelssohn wash bottle 3 to 25℃. The Mendelssohn wash bottle 3 can be filled with demineralized water for absorbing formaldehyde gas.

[0035] Example 5: It differs from Examples 1 to 4 in that: as shown in the appendix Figure 1 As shown, the top air inlet of the Meng-type washing bottle 3 is fixedly connected to the washing air pipe 13, the air outlet of the washing air pipe 13 extends to the bottom of the Meng-type washing bottle 3, and the top air outlet of the Meng-type washing bottle 3 is fixedly connected to the washing bottle air outlet pipe 14.

[0036] Example 6: Its difference from Examples 1 to 5 is as follows: (See attached) Figure 1 As shown, a first gas pipeline 9 is fixedly connected between the beaker outlet pipe 8 and the gas inlet of the gas washing pipe 13.

[0037] Example 7: Its difference from Examples 1 to 6 is as follows: (See attached) Figure 1 As shown, a second gas line 10 is fixedly connected between the gas outlet of the washing bottle outlet pipe 14 and the beaker inlet pipe 7.

[0038] Example 8: It differs from Examples 1 to 7 in that: as shown in the appendix Figure 1 As shown, both the first gas line 9 and the second gas line 10 are plastic hoses.

[0039] As needed, both the first gas pipeline 9 and the second gas pipeline 10 are made of plastic hoses, which can easily change the flow direction of the medium in the delivery pipeline. They can also enhance the sealing of the connection between the medium inlet and outlet of the beaker 2 with upper and lower nozzles, the wash bottle and the peristaltic pump 4 and the delivery pipeline, forming a closed loop, reducing gas leakage and improving the accuracy of formaldehyde extraction.

[0040] Example 9: It differs from Examples 1 to 8 in that: as shown in the appendix Figure 1 As shown, a bottle washing inlet valve 15 is fixedly installed on the first gas pipeline 9.

[0041] Example 10: It differs from Examples 1 to 9 in that, as shown in the appendix... Figure 1 As shown, a bottle washing outlet valve 16 is fixedly installed on the second gas pipeline 10.

[0042] After using this invention, firstly, the sealing performance of the device is improved, and the error in the formaldehyde content detection value of polyoxymethylene granules is reduced by more than 30%; secondly, the experimental exhaust gas is circulated and absorbed to avoid repeated experiments, thus improving the formaldehyde extraction efficiency; thirdly, this invention has a simple structure, using polytetrafluoroethylene sealing ring gaskets and plastic hoses, which is low in cost and highly adaptable.

[0043] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

[0044] The usage process of this utility model embodiment is as follows: First, polyoxymethylene granules are fed into the barrel 5 of the melt indexer 1. The melt indexer 1 heats the polyoxymethylene granules to 190°C, causing them to melt and release formaldehyde gas. Next, the formaldehyde gas in the barrel 5 enters the beaker 2 with upper and lower nozzles and then enters the Mendelian washing bottle 3 through the first gas line 9 and the gas washing pipe 13. The formaldehyde gas is dissolved and absorbed by the demineralized water contained in the Mendelian washing bottle 3 to obtain a formaldehyde solution. Then, the peristaltic pump 4 is started to extract the unabsorbed formaldehyde gas from the Mendelian washing bottle 3. Unabsorbed formaldehyde gas flows back to the beaker 2 with top and bottom nozzles through the wash bottle outlet pipe 14 and the second gas line 10. The formaldehyde gas in the beaker 2 with top and bottom nozzles then enters the Meng-type wash bottle 3 through the first gas line 9 for absorption and dissolution by demineralized water. Finally, the polyoxymethylene granules melt upon heating, releasing formaldehyde gas. After the formaldehyde gas is absorbed by the demineralized water circulating in the Meng-type wash bottle 3 for a period of time according to the above process, the wash bottle inlet valve 15 and the wash bottle outlet valve 16 are closed. The formaldehyde content of the formaldehyde solution in the Meng-type wash bottle 3 is determined by acetylacetone spectrophotometry.

Claims

1. A closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules, characterized in that... The device includes a melt flow indexer, a beaker with top and bottom nozzles, a Mendelssohn washing bottle, and a peristaltic pump. The melt flow indexer housing contains a material cylinder, and the bottom outlet of the material cylinder is correspondingly provided with an upward-opening beaker with top and bottom nozzles. The mouth of the beaker with top and bottom nozzles is sealed to the bottom of the melt flow indexer housing by a sealing ring gasket. The upper part of the beaker with top and bottom nozzles is fixedly connected to a beaker inlet pipe, and the lower part of the beaker with top and bottom nozzles is fixedly connected to a beaker outlet pipe. A first gas line is fixedly connected between the beaker outlet pipe and the top inlet of the Mendelssohn washing bottle, and a second gas line is fixedly connected between the top outlet of the Mendelssohn washing bottle and the beaker inlet pipe. A peristaltic pump is fixedly installed on the second gas line.

2. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 1, characterized in that... The sealing gasket is a polytetrafluoroethylene (PTFE) sealing gasket.

3. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 1 or 2, characterized in that... The beaker with upper and lower spouts also has a lifting platform at the bottom.

4. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 3, characterized in that... The bottom of the Meng-style washing bottle is also equipped with a heating furnace.

5. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 1, 2, or 4, characterized in that... The top air inlet of the Meng-style wash bottle is fixedly connected to a washing air pipe, the air outlet of the washing air pipe extends to the bottom of the Meng-style wash bottle, and the top air outlet of the Meng-style wash bottle is fixedly connected to a wash bottle air outlet pipe.

6. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 5, characterized in that... A first gas pipeline is fixedly connected between the beaker outlet pipe and the gas washing pipe inlet.

7. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 6, characterized in that... A second gas line is fixedly connected between the gas outlet of the washing bottle outlet pipe and the beaker inlet pipe.

8. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 1, 2, 4, 6, or 7, characterized in that... Both the first and second gas lines are made of plastic flexible hoses.

9. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to claim 8, characterized in that... A bottle washing inlet valve is fixedly installed on the first gas pipeline.

10. The closed experimental apparatus for extracting formaldehyde from polyoxymethylene granules according to any one of claims 1, 2, 4, 6, 7, or 9, characterized in that... A bottle washing outlet valve is fixedly installed on the second gas pipeline.

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